1: 94 percent / TsOH / CH2Cl2 / 0 degC, 30 min, room t., 1 h 2: 0.67 g / NaBH4 / methanol; tetrahydrofuran / 1 h / Ambient temperature 3: 0.61 g / NaOH / H2O; methanol / 4 h / Heating 4: benzenesulfonyl chlorid / pyridine / 0.25 h / 0 °C View Scheme

1: 94 percent / TsOH / CH2Cl2 / 0 degC, 30 min, room t., 1 h 2: 0.67 g / NaBH4 / methanol; tetrahydrofuran / 1 h / Ambient temperature 3: 0.61 g / NaOH / H2O; methanol / 4 h / Heating 4: benzenesulfonyl chlorid / pyridine / 0.25 h / 0 °C 5: pyridinium p-toluenesulfonate / ethanol / 4 h / 55 °C 6: 26 percent / triphenylphosphine, diethyl azodicarboxylate / tetrahydrofuran / Ambient temperature View Scheme

Multi-step reaction with 3 steps 1: 94 percent / TsOH / CH2Cl2 / 0 degC, 30 min, room t., 1 h2: 0.67 g / NaBH4 / methanol; tetrahydrofuran / 1 h / Ambient temperature3: 0.61 g / NaOH / H2O; methanol / 4 h / Heating  

Multi-step reaction with 2 steps 1: 94 percent / TsOH / CH2Cl2 / 0 degC, 30 min, room t., 1 h2: 0.67 g / NaBH4 / methanol; tetrahydrofuran / 1 h / Ambient temperature